The invention relates to a bit synchronization method based on sliding integration. The method comprises steps as follows: performing sliding integration calculation on bit data after sampling quantization, then comparing absolute values of an advanced integral value and a lagged integral value which are acquired through calculation with the sampling time period identical with an optimal integral value, then adjusting the acquired sampling position of the optimal integral value, and finally, stabilizing an optimal integral value point in a fixed sampling point position of a bit signal to realize bit synchronization. The method is simple in calculation, easy to realize, lower in resource consumption and applicable to various communication modulation modes. The invention also designs a bit synchronization system based on sliding integration. The system comprises a sampling quantization module, a sliding integration module, an integration latch module, a loop filter module and a latch period adjusting module. The system is simple in structure and quick and accurate in calculation.